Defrost bimetal for interrupting timed cycle icemaker during defrost{13 two timers

ABSTRACT

A refrigerator-freezer apparatus normally operating through freezing and defrosting portions of an operating cycle including a freezer compartment, a refrigeration system including a compressor and an evaporator for chilling the compartment to a subfreezing temperature, an icemaker producing ice bodies and having a motor for timing the period between harvests and for harvesting the ice bodies, an energizable defrost means for periodically warming the evaporator to defrosting temperature, an electrical circuit including the defrost means, an icemaker circuit including the icemaker motor and a temperature responsive switch common to both of these circuits and in heat exchange relationship with the evaporator for opening both circuits at an above freezing temperature of the evaporator so that the temperature responsive switch serves to terminate defrosting when the evaporator attains a substantially frost-free condition and to inactivate the icemaker motor also at above freezing temperatures in order to interrupt the timing function and avoid dumping water from the icemaker into the freezer compartment.

Elite Linstr'omner et all,

[ heir. 22, 11072 DEFUST BllMETAL FUR IINTERUPTIKNG 'llllMlED CYCLE IICEMAMIER DURENG llllElERUST-TW TlIMER Inventors: William .11. Linstromgerg; Duane C. Nichols, both of Evansville, Ind.

Assignee: Whirlpool Corporation Filed: ,llune 18, 1970 Appl. No: 417,521

ILLS. Cl. ..62/l.55, 62/234 llnt. Cl ..F25d 21/00 Field of Search ..62/233, 234, 155, 340

References Cited UNITED STATES PATENTS 3,541,806 11/1970 Jacobs ..62/233 3,312,080 4/1967 Dahlgren ..62/233 X Primary Examiner-William E. Wayner Attorney-James S. Nettleton, Thomas E. Turcotte, Burton H.

Baker, Gene A. Heth, Franklin C. l-laner, Anthony Niewyk, Robert L. Judd and l-lofgren, Wegner, Allen, Stellman & Mc- Cord [57] ABSTRACT A refrigerator-freezer apparatus normally operating through freezing and defrosting portions of an operating cycle including a freezer compartment, a refrigeration system including a compressor and an evaporator for chilling the compartment to a subfreezing temperature, an icemaker producing ice bodies and having a motor for timing the period between harvests and for harvesting the ice bodies, an energizable defrost means for periodically warming the evaporator to defrosting temperature, an electrical circuit including the defrost means, an icemaker circuit including the icemaker motor and a temperature responsive switch common to both of these circuits and in heat exchange relationship with the evaporator for opening both circuits at an above freezing temperature of the evaporator so that the temperature responsive switch serves to terminate defrosting when the evaporator attains a substantially frost-free condition and to inactivate the icemaker motor also at above freezing temperatures in order to interrupt the timing function and avoid dumping water from the icemaker into the freezer compartment.

4 Claims, 2 Drawing lFigures 40 acre MAKER SHUT- ore awn-cu (mower DEFROST TIMER THERMosTm' .32 DEFROST a HEATE 30 ICE MAKER u MOTOR Z8 I (5 v COMPRESSOR 69 DEF-'ROST Bl-METAL lDElFftOST lBlIMlETAL FOR llhlTERRlUPTllNG THE/1E1) CYCLE llClEMAhilElR DURHNG lDlElFlROST-TWO Til /HERE BACKGROUND OF THE INVENTTON lcemakers and particularly domestic icemakers provide automatic means for forming the ice bodies and for then dumping them into a receiver in the freezer compartment where they are maintained until used. Some of the icemakers now manufactured have means including thermostatically controlled motor means for harvesting the ice bodies as soon as a sufficiently low temperature has been achieved in the ice body portion of the maker to indicate that all liquid water has been frozen solid. Other types now manufactured use electrically operated timers to harvest the ice bodies on a schedule that is long enough between harvesting operations to insure that all water in the ice body portion of the maker has been frozen. The invention described and claimed herein is concerned with the timer operated types of icemakers.

SUMMARY OF THE INVENTlON One of the features of this invention is to provide an improved refrigerator apparatus that operates through an operating cycle having a freezing-icemaking portion and a defrosting portion with the apparatus including an evaporator, an icemaker having an operating and ice body dumping motor and a defrost heater that is periodically energized for removing frost from the evaporator in combination with a temperature responsive switch common to both the electrical circuit of the icemaker motor ad the circuit of the defrost heater, the temperature responsive switch being in heat exchange relationship with the evaporator so as to open at an above freezing temperature in the evaporator, with the result that this single switch common to both circuits functions to terminate the defrosting portion of the operating cycle and to serve as a delay switch to deenergize the icemaker motor and prevent dumping by the motor of liquid water from the ice maker.

Other features and advantages of the invention will be apparent from the following description of one embodiment thereof.

I BRIEF DESCRIPTION OF THE DRAWlNGS FIG. 1 is a side elevational view partially in vertical section illustrating a refrigerator apparatus embodying the invention.

FIG. 2 is a wiring diagram of the electrical portion of the apparatus of FIG 1.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In the refrigerator-freezer of FIG. 1 there is provided an insulated cabinet 11 having an upper freezer compartment 12 and a lower refrigerator compartment 13 each having a front access opening normally closed by its own door 14 and 15, respectively.

Separating the upper freezer compartment 12 from the lower refrigerator compartment 13 is an inclined generally horizontal insulated wall or mullion 16. Overlying this wall 16 is a customary refrigerant evaporator 17 composed of a serpentine tube 18 and spaced vertically arranged fins 19 interconnecting the tubes and in heat exchange relationship therewith.

Located at the back of the freezer compartment 12 is a motoroperated air circulating fan 20 in an air conduit housing 21. This fan 20 is positioned to draw air directly from the rear of the evaporator and circulate it through the upper freezer compartment 12 as indicated by the arrows 22 and through the refrigerator compartment 13 as indicated by the arrows 23. As shown in FlG. 1 the two streams of air 22 and 23 are returned to the evaporator 17 at the front thereof for passage rearwardly between the fins 19 and back into the fan 20 in the customary manner.

Located in the freezer compartment 12 so as to be in heat exchange relationship with the subfreezing air therein is an automatic icemakcr 24 of customary construction having a motor operated part 25 and an ice body forming part 26 operated thereby.

The refrigerator apparatus illustrated comprises a refrigeration system including a compressor (not shown), the evaporator 17 and a refrigerant condenser (not shown) as is customary in a refrigeration system of this type.

The electrical circuit is illustrated in the wiring diagram of HO. 2. As is shown here, in addition to a compressor motor 27, the circuit includes an icemakcr motor 28, an icemakcr shutoff switch 29, which is normally closed as shown but which is automatically opened to deenergize the motor 28 when a sufficient amount of ice bodies have been formed, this being a customary automatic control in. automatic icemalcers. a defrost heater 311 which as illustrated comprises a heater resistance wire in heat exchange relationship with the evaporator 17 to heat the entire evaporator to an above freezing temperature so as to melt ice thereon which thereupon flows from the refrigerator through a customary drain tube 31.

In addition, the circuit of FlG. 2 includes a cabinet thermostat 32 located within the refrigerator compartment 13 to cycle the compressor 27 on and off to provide refrigeration as needed.

In the electrical circuit there is also provided a defrost ti mcr 33 that includes an operating defrost motor 3 1. The defrost timer 33 functions by causing the motor 34 to retain a movable switch arm 35 in engagement with a switch contact 36 as illustrated during the refrigeration portion of the operating cycle to energize the compressor 27 and thus operate the refrigeration system and then periodically move the switch arm 35 away from engagement with the contact 36 into ongagement with a second switch contact 37 thereby energizing the defrost heater 311.

The wiring diagram, therefore, includes an electrical lead 3% that interconnects the defrost contact 37 in series with the heater 30 which is itself in series with a temperature rcspon sive bimetal switch 39 which is identified in FIG. 2 as a defrost bimetal. Thus when the timer motor 34! has moved the switch arm 35 into engagement with the contact 37 the electric lead 38 of the circuit is connected across electrical supply lines 111 and fl-ll thereby energizing the defrost heater 311 through switch 39.

The wiring diagram includes a second or icemakcr electrical circuit which includes an electric lead 412 interconnecting in series the ice maker shutoff switch 2.9. and the icemakcr motor 28. Motor 211 is in turn connected to the defrost bimctul switch 39 by a lead 50. In other words, the switch 39 which opens at a high temperature, that is above freezing. is common to both the first and second electrical circuits so that both circuits are opened at an above freezing temperature in the evaporator 17 and thus in the freezer compartment. In order to have this heat exchange relationship with the evaporator the switch 39 is mounted on or in close proximity to a heat conducting portion 43 of the evaporator as illustrated in FIG. 1.

With this arrangement the temperature responsive switch 39 which may be a switch that is ordinarily present in the operating electrical circuit of the refrigeration system serves the dual function of terminating defrosting when the evaporator 17 is substantially frost free by opening the circuit to the heater 30 and also for deenergizing the icemaker motor 28 during periods of elevated temperature to delay the timing of the freezing cycle and prevent the accidental dumping of liquid water from the ice body forming portion 2b of the icemaker.

This temperature responsive switch 39 is necessary because in the circuit as illustrated the icemaker motor 21% is energized continuously so long as the switch 29 and limiting switch 39 are closed.

ln a typical apparatus embodying the invention, and presented here as an example only. the. temperature responsive switch 39 was designed to open at the relatively high tem: perature of about 55 F. and remain open until the temperature dropped to about 20 F. it did not: open again until the temperature again reached 55 F. during the next defrosting operation.

The foregoing disclosure of a specific embodiment is illustrative of the broad inventive concepts comprehended by the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A refrigerator apparatus having an operating cycle including a freezing icemaking portion and a defrosting portion, comprising: insulated walls defining a freezer compartment; a refrigeration system including a compressor and an evaporator for chilling said compartment to a subfreezing temperature; an icemaker in said compartment for producing ice bodies and having a timing and harvesting motor energizable in harvesting said ice bodies; defrost means including a timeroperated switch for periodically warming said evaporator to defrosting temperature; a first electrical circuit for energizing said defrost means; a second electrical circuit including said icemaker timing and harvesting motor; and a temperature responsive switch means common to both said first and second circuits and in heat exchange relationship with said evaporator for opening said circuits at an above freezing temperature of said evaporator, thereby serving to terminate defrosting upon the evaporator attaining a substantially frost-free condition and to inactivate the icemaker at above freezing temperatures.

2. The apparatus of claim 1 wherein there is provided a third electrical circuit including a compressor and a thermo stat switch means for energizing said compressor to maintain said subfreezing temperature.

3. The apparatus of claim 2 wherein there is provided control means for controlling the operation of said compressor, said defrost means and said icemaker.

4. The apparatus of claim 3 wherein said control means comprises a timer motor, an electrical circuit energizing said motor, and a plurality of timer switch means operated by said motor, one said switch means being in said first circuit and another said switch means being in said third circuit. 

1. A refrigerator apparatus having an operating cycle including a freezing icemaking portion and a defrosting portion, comprising: insulated walls defining a freezer compartment; a refrigeration system including a compressor and an evaporator for chilling said compartment to a subfreezing temperature; an icemaker in said compartment for producing ice bodies and having a timing and harvesting motor energizable in harvesting said ice bodies; defrost means including a timer-operated switch for periodically warming said evaporator to defrosting temperature; a first electrical circuit for energizing said defrost means; a second electrical circuit including said icemaker timing and harvesting motor; and a temperature responsive switch means common to both said first and second circuits and in heat exchange relationship with said evaporator for opening said circuits at an above freezing temperature of said evaporator, thereby serving to terminate defrosting upon the evaporator attaining a substantially frost-free condition and to inactivate the icemaker at above freezing temperatures.
 2. The apparatus of claim 1 wherein there is provided a third electrical circuit including a compressor and a thermostat switch means for energizing said compressor to maintain said subfreezing temperature.
 3. The apparatus of claim 2 wherein there is provided control means for controlling the operation of said compressor, said defrost means and said icemaker.
 4. The apparatus of claim 3 wherein said control means comprises a timer motor, an electrical circuit energizing said motor, and a plurality of timer switch means operated by said motor, one said switch means being in said first circuit and another said switch means being in said third circuit. 